mk476734929-优快云博客

原创 207. Course Schedule

There are a total ofncourses you have to take, labeled from0ton-1.Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair...

2019-11-11 22:08:29 143

原创 Word Break

Given anon-emptystringsand a dictionarywordDictcontaining a list ofnon-emptywords, determine ifscan be segmented into a space-separated sequence of one or more dictionary words.Note:The ...

2019-04-18 15:57:37 133

原创 Triangle

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.For example, given the following triangle[ [2], [3,4], [6,5...

2019-04-17 21:08:54 173

原创 Unique Binary Search Trees I II

Givenn, how many structurally uniqueBST's(binary search trees) that store values 1 ...n?Example:Input: 3Output: 5Explanation:Given n = 3, there are a total of 5 unique BST's: 1 ...

2019-04-17 19:51:39 117

原创 91. Decode Ways

A message containing letters fromA-Zis being encoded to numbers using the following mapping:'A' -> 1'B' -> 2...'Z' -> 26Given anon-emptystring containing only digits, determine t...

2019-04-16 16:12:05 104

原创 90. Subsets II

Given a collection of integers that might contain duplicates,nums, return all possible subsets (the power set).Note:The solution set must not contain duplicate subsets.Example:Input: [1,2,2]...

2019-04-13 17:08:07 100

原创 Gray Code

The gray code is a binary numeral system where two successive values differ in only one bit.Given a non-negative integernrepresenting the total number of bits in the code, print the sequence of gr...

2019-04-13 15:56:09 148

原创 Search in Rotated Sorted Array II

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e.,[0,0,1,2,2,5,6]might become[2,5,6,0,0,1,2]).You are given a target value to search. If found ...

2019-04-10 21:59:18 167

原创 Sort Colors

75.Sort ColorsGiven an array withnobjects colored red, white or blue, sort themin-placeso that objects of the same color are adjacent, with the colors in the order red, white and blue.Here, w...

2019-04-10 20:58:48 87

原创 Remove Duplicates from Sorted Array II

Given a sorted arraynums, remove the duplicatesin-placesuch that duplicates appeared at mosttwiceand return the new length.Do not allocate extra space for another array, you must do this bymod...

2019-04-10 20:50:58 102

Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically n...

2019-04-10 18:10:15 137

原创 Search a 2D Matrix

Write an efficient algorithm that searches for a value in anmxnmatrix. This matrix has the following properties:Integers in each row are sorted from left to right. The first integer of each row...

2019-04-08 20:03:21 95

原创 71. Simplify Path

Given anabsolute pathfor a file (Unix-style), simplify it. Or in other words, convert it to thecanonical path.In a UNIX-style file system, a period.refers to the current directory. Furthermore,...

2019-04-08 12:17:37 127

原创 63. Unique Paths II

A robot is located at the top-left corner of amxngrid (marked 'Start' in the diagram below).The robot can only move either down or right at any point in time. The robot is trying to reach the bo...

2019-04-01 09:37:10 84

原创 62. Unique Paths

A robot is located at the top-left corner of amxngrid (marked 'Start' in the diagram below).The robot can only move either down or right at any point in time. The robot is trying to reach the bo...

2019-03-31 21:28:46 96

原创 60. Permutation Sequence

The set[1,2,3,...,n]contains a total ofn! unique permutations.By listing and labeling all of the permutations in order, we get the following sequence forn= 3:"123" "132" "213" "231" "312"...

2019-03-31 16:23:06 113

原创 56. Merge Intervals

Given a collection of intervals, merge all overlapping intervals.Example 1:Input: [[1,3],[2,6],[8,10],[15,18]]Output: [[1,6],[8,10],[15,18]]Explanation: Since intervals [1,3] and [2,6] overlaps...

2019-03-28 21:39:19 122

原创 Jump Game

Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximum jump length at that position.Determine if yo...

2019-03-24 23:28:44 109

原创 50. Pow(x, n)

Implementpow(x,n), which calculatesxraised to the powern(xn).Example 1:Input: 2.00000, 10Output: 1024.00000Example 2:Input: 2.10000, 3Output: 9.26100Example 3:Input: 2.00000, ...

2019-03-23 23:19:44 96

原创 47. Permutations II

Given a collection of numbers that might contain duplicates, return all possible unique permutations.Example:Input: [1,1,2]Output:[ [1,1,2], [1,2,1], [2,1,1]]解法：和Permutations解法类似，...

2019-03-23 21:43:54 115

原创 Permutations

Given a collection ofdistinctintegers, return all possible permutations.Example:Input: [1,2,3]Output:[ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1]]解法：利用递归，模拟树的输出情...

2019-03-21 16:58:31 122

原创 43. Multiply Strings

Given two non-negative integersnum1andnum2represented as strings, return the product ofnum1andnum2, also represented as a string.Example 1:Input: num1 = "2", num2 = "3"Output: "6"Exampl...

2019-03-16 18:02:23 76

原创 40. Combination Sum II

Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations incandidateswhere the candidate numbers sums totarget.Each number incandidatesmay...

2019-03-14 21:27:34 69

原创 39. Combination Sum

Given asetof candidate numbers (candidates)(without duplicates)and a target number (target), find all unique combinations incandidateswhere the candidate numbers sums totarget.Thesamerepeat...

2019-03-14 16:16:51 88

原创 Find First and Last Position of Element in Sorted Array

Given an array of integersnumssorted in ascending order, find the starting and ending position of a giventargetvalue.Your algorithm's runtime complexity must be in the order ofO(logn).If the...

2019-03-05 21:55:13 151

原创 33. Search in Rotated Sorted Array

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e.,[0,1,2,4,5,6,7]might become[4,5,6,7,0,1,2]).You are given a target value to search. If found ...

2019-02-28 21:16:36 87

原创 4. Median of Two Sorted Arrays

There are two sorted arrays nums1 and nums2 of size m and n respectively.Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).You may assume nums1 and n...

2019-02-27 10:22:57 95

原创 Next Permutation

Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangement is not possible, it must rearrange it as the lowest possible o...

2019-02-26 13:03:05 82

原创 29. Divide Two Integers

Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator.Return the quotient after dividing dividend by divisor.The integer division sho...

2019-02-25 10:11:58 70

原创 Swap Nodes in Pairs

Given a linked list, swap every two adjacent nodes and return its head.You may not modify the values in the list's nodes, only nodes itself may be changed. Example:Given 1->2->3->4, ...

2019-02-21 21:41:18 72

原创 18. 4Sum

Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of tar...

2019-02-21 09:53:19 76

原创 Letter Combinations of a Phone Number

Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent.A mapping of digit to letters (just like on the telephone buttons) is giv...

2019-02-20 21:13:51 96

原创 16. 3Sum Closest

Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three integers. You may assume that each input would ...

2019-02-19 22:07:25 85

原创 12. Integer to Roman

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.Symbol ValueI 1V 5X 10L 50C 100D ...

2019-02-19 20:48:21 72

原创 371. Sum of Two Integers

Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.Example 1:Input: a = 1, b = 2Output: 3Example 2:Input: a = -2, b = 3Output: 1解法：每轮使用异或保留...

2019-02-19 19:42:18 169

原创 Valid Perfect Square

Given a positive integer num, write a function which returns True if num is a perfect square else False.Note: Do not use any built-in library function such as sqrt.Example 1:Input: 16Output: t...

2019-02-19 17:28:22 82

原创 Intersection of Two Arrays

Given two arrays, write a function to compute their intersection.Example 1:Input: nums1 = [1,2,2,1], nums2 = [2,2]Output: [2]Example 2:Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]Output: [...

2019-02-19 10:01:49 78

原创 342. Power of Four

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.Example 1:Input: 16Output: trueExample 2:Input: 5Output: falseFollow up: Could you solve it witho...

2019-02-18 18:10:30 73

原创 Reverse Vowels of a String

Write a function that takes a string as input and reverse only the vowels of a string.Example 1:Input: "hello"Output: "holle"Example 2:Input: "leetcode"Output: "leotcede"Note:The vowel...

2019-02-18 17:53:55 119

原创 Range Sum Query - Immutable

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.Example:Given nums = [-2, 0, 3, -5, 2, -1]sumRange(0, 2) -> 1sumRange(2, 5) -> -1sum...

2019-02-18 17:29:02 73

四则运算源代码待调试。。

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